Device for producing reenforced-concrete tubes by the action of centrifugal force



EHNDER REENFORCE 2 1,752,627 DEVICE FOR PRODUCING D CONCRETE TUBES BY THE ACTION OF CENTRIFUGAL FORCE Filed March 27'. 1929 April 1, 1930.

Patented Apr. 1, 1 930 UNITED STATES PATENT PAUL ZEHNIDER, OF LUCERNE, SWITZERLAND, ASSIGNOR TO THE FIRM INTERNA- TIONALE SIEGWARTBALKENGESELLSCHAFT'IN LUZERN, 0F LUCERNE, SWITZEB LAND DEVICE FOR PRODUCING REENFORGED-CONCRETE TUBES BY THE ACTION OF GEN- TRIFUGAL FORCE Application filed March 27, 1929, Serial No. 350,256, and in Switzerland January 24, 1929.

The interior wall surfaces of reenforced concrete tubes must be as smooth as possible, so that but a small frictional resistance is offered to the liquid passing through the tube and that a good protection of the same against corrosion is ensured, rough portions in the surface being the points in which the corroding effect starts. In reenforced concrete tubes, produced by action of centrifugal force, it may happen that parts of the material of heavier grain accumulate in one place and, despite of the effect of centrifugal action, project from the smooth portions of the interior surface of the tube.

The object of the invention is to provide a device for smoothing the interior wall surface of reenforced concrete tubes during their production by action of centrifugal force which is equipped with a smoothing member rotatably mounted on a material charging member and with means for moving the said smoothing member from its inoperative into an operative position.

In the accompanying drawing an embodiment of the device, according to the invention, is illustrated, by way of example only, in which:

Fig. 1 is an elevation of a material charging member comprising the member for smoothing;

Fig. 2 is a plan view of Fig. 1,

Figs. 3 and 4 are sections on a larger scale, of details and Fig. 5 is a section, on a larger scale through the device and through a pipe, showing the device in inoperative as well as operative position.

Referring to the drawing, 1 denotes the material charging member which is formed in the manner of'an oblong trough, open on top, and which is mounted on a carriage 2. The carriage 2 is adapted to'run on rails 6 by means of wheels 3, 4 and 5; the wheels 5 grip under flanges provided on the rails in order to avoid a downward tilting of the material charging barrel. The latter is rotatably mounted and is adapted to be turned about its axis by means of hand wheels 7 to permit of discharging the material whilst the hand wheels 8 enable the material charging barrel to be entered into the mould 9, as

indicated in chain lines in Fig. 1, for the purpose of charging the same with material. The mould is mounted between a chuck 10 and a chuck plate 11 to which, by means not shown, .a quick rotation is imparted, for instance, in a manner as described in my U. S. Patent No. 1,521,264: filed Dec. 12, 1924. The material contained in the charging barrel 1, when discharged into the mould, forms a uniform annular layer 12 in the mould 9 by centrifugal action as shown in Fig.5.

Now, in order to press projecting portions of the material back into the layer and, consequently, to smooth the interior surface of the tube the following device is provided for:

A shaft 13 extending alongside of the trough 1 is rotatably mounted thereon and provided with fixed arms 14. 'To the latter for instance by means of bolts, a. curved smoothing blade 15 is exchangeably connected, such as shown in full lines, in its in operative position, in Fig; 5. In this position the shaft 13 is held by a spring loaded stop pin 16 cooperating with a disk 17 which is provided with a recess for engaging the stop pin 16. The latter can be retracted from its locking position simply by applying a pull to its end portion 18 which isbent over to form a handle. The smoothing blade 15 is somewhat shorter than the length of the tube to be treated. To enable smoothing along the full length of the tube the shaft 13, and the smoothing blade 15 together with it, is arranged to be somewhat axially displaceable in that a lever 19 engages the shaft between two shoulders 20. The lever 19 is rotatably mounted on the material charging barrel 1 in the vertical plane passing through the shaft 18 (Fig. In order to move the smoothing blade 15 in its operative position shown in dotted lines in Fig. 5 in which it effects a polishing action on the interior wall of the tube 12, the shaft 13 is turned by means of the lever 21 and, thereby, the curved portion of the smoothing blade 15 is pressed against the interior wall.

The smoothing blade 15 is of such a width that will permit of polishing tubes of 5080 cm. in diameter; for tubes of 85-120 cm. in diameter a wider smoothing blade 15' is employed such as shown in chain lines in Fig. 5. For larger tubes a larger material charging barrel is required (for tubes smaller than 50 cm. in diameter a smaller one) on which, 5 in similar manner, smoothing blades of dif* ferent size are exchangeably arranged.

I claim: 1. In a device for smoothing the interior walls of concrete tubes during their producm tion by centrifugal action, the combination of a. material charging member adapted to receive the material, a smoothing member rotatably mounted on said material charging member, and means for moving the smoothing member from its inoperative into an operative osition in which it acts on the inter'ior o the tube.

2. In a device of the type described, the combination of a material charging member adapted to receive the material, a smoothing member shaped in the manner of a curved blade, a shaft rotatably mounted on said material charging member in parallel position to the axis of the same, a number of arms fixed to said shaft for exchangeably connecting the smoothing member thereto and means for moving the smoothing member from its inoperative into an operative position in which it acts on the interior of the tube.

3. In a device of the type described, the combination of a material charging member adapted to receive the material, a smoothing member shaped in the manner of a curved blade, a shaft rotatably mounted on said inaterial charging member in arallel position to the axis of the same and arranged to'be longitudinally displaceable thereon, a number of arms fixed to said shaft for exchangeably connecting the smoothing member thereto, means for moving the smoothing member from its ino erative into an'operative osition in whic it acts on the interior 0 the tube, and means for longitudinally displacing the smoothing member to permit ofpol- :5 ishing the interior wall of a tube along the full length of the same.

In testimony whereof I have signed my name to this specification.

PAUL ZEHN'DER. 

